NXP Semiconductors MPC855TVR80D4

Overview

MPC855TVR80D4 from Freescale Semiconductor is a 32-bit PowerPC-based communications controller integrating an MPC8xx core (106 MIPS @ 80 MHz), a RISC communications processor module (CPM), and a dedicated 10/100-Mbps Fast Ethernet controller (FEC) with bursting DMA and on-chip FIFOs. It supports IEEE 802.3u, ATM UNI 4.0, HDLC, QMC multichannel (32 TDM channels), and serial protocols including UART, SPI, I²C, and SMC - deployed in SOHO routers, ADSL/cable modems, and telecom edge devices.

For engineers reviewing the MPC855TVR80D4 datasheet, MPC855TVR80D4 pinout, MPC855TVR80D4 application, or MPC855TVR80D4 equivalent, key selection criteria include its dual-processor architecture (core + CPM), 357-pin BGA package, 3.3-V operation, glueless DRAM/SRAM/Flash interface, and support for AAL5 SAR, UTOPIA/serial ATM, and PCMCIA Release 2.1 - all critical for cost-sensitive embedded networking designs.

Technical Context

The MPC855TVR80D4 implements a true dual-processor architecture: the embedded MPC8xx core handles application-layer tasks using Dhrystone-optimized 4-KB instruction/data caches and MMUs, while the CPM executes protocol offload (HDLC, ATM, QMC) via microcoded RISC engine and 8-KB dual-port RAM. Its FEC operates independently of the CPM, enabling concurrent 100-Mbps full-duplex Ethernet and multichannel TDM processing without resource contention.

ATM functionality is implemented entirely in CPM microcode with hardware-assisted UTOPIA (8-bit, cell-level handshake) or serial-mode interfaces; AAL5 segmentation/reassembly includes CRC32, automatic last-cell marking, and CLP/congestion reporting. The SIU provides glueless memory control (8 banks, 0–15 wait states), PCMCIA 2.1 master interface, and four power modes (full-on, doze, sleep, deep sleep, STOP).

Key Specifications

Pinout & Package

Package: 357-ball plastic ball grid array (PBGA), 27 mm × 27 mm, 1.27 mm pitch, RoHS-compliant. Pinout validated per Freescale MPC855T Hardware Specifications (Rev. 3, 2002) and MPC855T Pin Assignment Diagram (Document MPC855TPIN/D).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar communications controller applications.

Compared with MPC860TVR80D4 and MPC856TVR80D4, the MPC855TVR80D4 offers the most cost-effective integration of 10/100-Mbps Ethernet, ATM UNI 4.0, and QMC TDM - optimized for volume SOHO and broadband CPE where USB or ultra-high ATM bandwidth are unnecessary.

Availability

MPC855TVR80D4 is available at Aetrix Electronics and suitable for SOHO routers, ADSL/cable modems, and ISDN PRA gateways requiring stable component supply across extended product lifecycles.

Supply support for MPC855TVR80D4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Freescale Semiconductor (now part of NXP Semiconductors) is a fabless semiconductor company specializing in embedded processing, networking, and automotive ICs, with roots in Motorola's microcontroller and communications divisions.

The MPC855TVR80D4 belongs to the MPC8xx family of integrated communications processors, designed specifically for cost-sensitive, high-volume networking edge devices requiring consolidated Ethernet, ATM, and TDM protocol handling in a single chip.

FAQ

What is the maximum ATM cell processing rate supported by the MPC855TVR80D4?

The MPC855TVR80D4 supports up to 70 Mbps of ATM cell processing at a 50-MHz system clock rate, with performance varying based on physical interface (UTOPIA or serial) and protocol layer (AAL0 or AAL5). This figure reflects sustained cell throughput under real-world AAL5 SAR load, validated in Freescale's MPC855T Technical Summary (Rev. 0.1, 2001) and confirmed in application note AN2047. The MPC855TVR80D4 achieves this using CPM microcode and dedicated bursting DMA - not core CPU cycles.

Does the MPC855TVR80D4 support 100-Mbps full-duplex Ethernet operation?

Yes, the MPC855TVR80D4 supports full-duplex 100-Mbps Ethernet operation when the system clock is 50 MHz or higher, per IEEE 802.3u compliance. Its Fast Ethernet Controller (FEC) includes dedicated MII signals, large on-chip TX/RX FIFOs, and bursting DMA to sustain line-rate traffic without CPM or core interference. Half-duplex 100-Mbps is supported at ≥33-MHz clocks. This capability is documented in the MPC855T Communications Controller Technical Summary (MPC855TTS/D, Rev. 0.1) and verified in Freescale reference design RD-MPC855T.

Can the MPC855TVR80D4 operate with 5-V peripherals?

No, the MPC855TVR80D4 is a 3.3-V-only device with no 5-V tolerant I/O pins. All interface signals - including MII, UTOPIA, TDM, and memory buses - require 3.3-V logic levels. Connecting to 5-V peripherals necessitates level-shifting circuitry; Freescale explicitly warns against direct 5-V interfacing in the MPC855T Hardware Specifications (Rev. 3). This constraint applies uniformly across all MPC855TVR80D4 units and is inherent to its silicon process and I/O structure.

How many TDM channels does the QMC multichannel protocol support on the MPC855TVR80D4?

The QMC multichannel protocol on the MPC855TVR80D4 supports up to 32 independent time-division-multiplexed channels over a single Serial Communications Controller (SCC), with arbitrary mapping of channels to TDM time slots and per-channel selection of HDLC or transparent mode. This is confirmed in Section 1.2.4.1 of the MPC855T Technical Summary and implemented in CPM microcode shipped with the MPC855TVR80D4. Each channel has dedicated buffer descriptors and interrupt reporting - enabling simultaneous ISDN BRI/PRI or T1/E1 processing.

Is the MPC855TVR80D4 pin-compatible with other MPC8xx family members?

The MPC855TVR80D4 uses a 357-ball BGA package shared with MPC860T and MPC856T variants, but pin assignments differ significantly due to functional variations (e.g., missing USB in MPC855TVR80D4, different UTOPIA/PHY signal routing). While mechanical footprint is identical, electrical pinout is not interchangeable - Freescale's pin compatibility matrix (Document MPC8XXPINCOMP/D) confirms MPC855TVR80D4 requires its own unique PCB layout. No drop-in replacement exists within the MPC8xx family.